Intracranial Non-traumatic Aneurysms in Children and Adolescents.

2013·0.36 MB·English

by  Sorteberg, Angelika

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Current Pediatric Reviews, 2013, 9, 343-352 343
Intracranial Non-traumatic Aneurysms in Children and Adolescents
Angelika Sorteberg* and Daniel Dahlberg
Dept of Neurosurgery, Oslo University Hospital – Rikshsospitalet, The National Hospital, Oslo, Norway
Abstract: An intracranial aneurysm in a child or adolescent is a rare, but potentially devastating condition. As little as ap-
proximately 1200 cases are reported between 1939 and 2011, with many of the reports presenting diverting results. There
is consensus, though, in that pediatric aneurysms represent a pathophysiological entity different from their adult counter-
parts. In children, there is a male predominance. About two-thirds of pediatric intracranial aneurysms become sympto-
matic with hemorrhage and the rate of re-hemorrhage is higher than in adults. The rate of hemorrhage from an intracranial
aneurysm peaks in girls around menarche. The most common aneurysm site in children is the internal carotid artery, in
particular at its terminal ending. Aneurysms in the posterior circulation are more common in children than adults. Chil-
dren more often develop giant aneurysms, and may become symptomatic from the mass effect of the aneurysm (tumor-
like symptoms). The more complex nature of pediatric aneurysms poses a larger challenge to treatment alongside with
higher demands to the durability of treatment. Outcome and mortality are similar in children and adults, but long-term
outcome in the pediatric population is influenced by the high rate of aneurysm recurrences and de novo formation of in-
tracranial aneurysms. This urges the need for life-long follow-up and screening protocols.
Keywords: Cerebral vasospasm, giant aneurysm, intracranial aneurysm, outcome, pediatric, subarachnoid hemorrhage.
INTRODUCTION and connective tissue diseases including Marfan`s syndrome,
coarctation of the aorta, Ehler-Danlos syndrome type IV and
Intracranial aneurysms occur rarely in children and ado-
fibromuscular dysplasia [7]. Other associated medical condi-
lescents. Although the literature on intracranial aneurysms in
tions comprise polycystic kidney disease, tuberous sclerosis,
individuals younger than 18 years is limited and to some
sickle cell anemia, hereditary hemorrhagic telangiectesis
degree inconsistent, there seems to be consent in that pediat-
(Osler-Weber-Rendu disease), Klippel-Trenaunay-Weber
ric aneurysms represent an independent condition different
syndrome and alpha-1-antitrypsin deficiency. Underlying
to their adult counterparts. Reports and institutional experi-
comorbidity is found in up to one third of the children with
ences with pediatric aneurysms are small case series ranging
intracranial aneurysms [7-9].
from three individuals [1] to 77 cases [2]. So far, until larger
series applying a multi-center approach are performed and Infectious etiology of an intracranial aneurysm (often de-
published, review of the literature is the best approach to noted as “mycotic aneurysm”) is more common in children
understanding and recognizing this seldom condition. The than in adults [4] and accounts for up to 15% of all pediatric
present review focuses on intracranial pediatric aneurysms of aneurysms [4, 10, 11]. The most common infectious agens is
non-traumatic origin as the latter actually are pseudoaneu- bacterial, not fungal [4] and may be caused by bacterial en-
rysms caused by endothelial damage and thereby form a dif- docarditis or syphilis. The most common causing organisms
ferent pathofysiological entity. isolated are staphylococcus aureus and streptococcus viri-
dans [12]. Children with immunodeficiency diseases like
HIV may be especially prone to infectious aneurysms. [13-
ETIOLOGY 15]. By reviewing a total of 431 cases reported in the litera-
In the adult population, certain risk factors are linked to ture [7, 8, 11, 13, 16-29] we found 8,4% of the cases to be of
the development of intracranial aneurysms, including smok- infectious etiology.
ing, arterial hypertension, age, gender and excessive chronic
alcohol intake [3]. None of these are likely to contribute in
INCIDENCE
the formation of aneurysms in children. Many pediatric in-
tracranial aneurysms are related to arterial dissection. Cere- Pediatric intracranial aneurysms are acquired lesions as
bral arteriovenous malformations may carry aneurysms on autopsy studies could not disclose aneurysms at birth [13].
feeding arteries. Approximately 5-10% of childhood cerebral The acquisition of an intracranial aneurysm during birth has
aneurysms are related to head trauma [4]. been reported by Piatt and Clunie [30]. Aneurysms diag-
nosed in children younger than 1 year are extremely seldom,
Some comorbidities are related to a larger risk of aneu-
Buis et al. [9] found 131 cases in his review searching for
rysm formation, amongst them reticular fiber deficiency [5],
publications from before 1966 until 2005.
gene mutations interfering with the extracellular matrix [6]
The incidence of aneurysmal hemorrhage was found to
be 0.05-0.09 per 100000 person-years in children younger
*Address correspondence to this author at the Dept of Neurosurgery, Oslo
than 15 years, whereas it increases to 0.5 respectively, in
University Hospital – Rikshsospitalet, The National Hospital. 0454 Nyda-
those between 15 and 19 years [31]. Jordan et al. [31] num-
len, Oslo, Norway; Tel: [phone]; Fax: [phone]; E-mail: angeli-
[email protected] bers indicate a 35 times larger chance of aneurysmal hemor-

1875-6336/13 $58.00+.00 © 2013 Bentham Science Publishers
344 Current Pediatric Reviews, 2013, Vol. 9, No. 4 Sorteberg and Dahlberg
rhage in adults as compared to children. The fraction of pe- ported in the literature [7, 8, 11, 13, 16-29] the male:female
diatric aneurysms within the total volume of patients with ratio is 1.42:1. The age distribution within sexes differs.
intracranial aneurysms varies (Kakarla et al. 1% [16], Huang Boys show a gradual increase in frequency with increasing
et al. [32] 1,4%, Sharma et al. 4% [33], Krishna et al. [17] age (Fig. 1), whereas girls peak around menarche, resulting
4,6%) with 0,95% in Fulkerson et al. `s [18] material and in a female predominance at ages 14 and 15 (Fig. 1).
6,8% in Lasjaunias et al. [13] series at the extremes.
CLINICAL PRESENTATION
Intracranial aneurysms in adults occur twice as often in
Subarachnoid hemorrhage (SAH), is by far the most
females than in males [3]. This does not hold true in chil-
common presenting symptom of intracranial aneurysms
dren. Lasjaunias et al. [13] observed a male to female ratio
[7, 8, 11, 16-18, 22, 28, 29, 33, 35-38]. In some reports,
of 3:2, however, the ratio became 1:5 for children younger
however, the rate of SAH in children was far lower, be-
than 2 years. Krishna et al. [17] reported a 1,75:1
tween 20-30% [2, 8, 39]. By reviewing 1165 published
male:female ratio, but they had no patients younger than 5
cases, 72% of those 0-18 years old presented with SAH
years. Another study from India, by Sharma et al. [33] found
(Table 1), which is less than the 89% reported for the
a 2,2:1 male:female ratio; however, most of their patients
adult population [38].
(82%) were older than 10 years, with only 4 children being
younger than 5 years. Other authors reported a more even The presentation with SAH has been claimed to be to
male/female distribution [7, 22]. Reviewing 431 cases re- some degree age-dependent with peaks at ages 2-5 and in

Fig. (1). Distribution of age at diagnosis of the intracranial aneurysm in males (light grey columns) versus females (dark grey columns).
Scale on the right shows the male/female ratio with values above “1” (dotted line) indicating male predominance. Data from [7, 8, 11, 13, 16-29].

Table 1. Summary of Publications on Pediatric Intracranial Aneurysms

Males Good Giant Posterior Circu- Good outcome Mortality
Year Authors Cases n= SAH (%)
(%) grade (%) aneurysm (%) lation (%) (%) (%)
1939- Accumulated data 965 60 74 51 21 19 62 24
2009
From the review of Jian et al. [35] (3-77) (33-92) (33- (0-96) (0-54) (0-46) (13-95) (0-100)
100)
Range given in ( )
2007 Sharma et a.l [33] 55 69 78 86 19 12 90 9
2008 Songsaeng et al. [21] 8 63 25 63 25 50 63 0
2008 Stiefel et al. [22] 12 33 100 75 8 33 75 17
2009 Liang et al. [20] 24 58 46 88 32 36 92 4
2009 Lv et al. [23] 25 80 44 Not given 68 60 96 4
2010 Kakarla et al. [16] 48 58 35 83* 23 24 92 3
2011 Fulkerson et al. [18] 28 43 68 71 7 21 92 7
Total 1165 65 72 68 19 21 68 19
*: based on GCS scores at admission
Pediatric Aneurysms Current Pediatric Reviews, 2013, Vol. 9, No. 4 345
adolescents older than 15 years [4]. Krings et al. [4] attrib- 11, 13, 17-22, 24, 25, 27, 29], there was no statistical differ-
uted this to the high incidence of dissecting aneurysms in ence in clinical grade between girls and boys.
those 2-5 years old and the prevalence of saccular “adult”
The lower incidence of hemorrhagic presentation in chil-
aneurysms in those > 15 years. Fig. (2) illustrates the age
dren is due to the high incidence of giant aneurysms that
distribution for aneurysmal hemorrhage, as accumulated
present with tumor effect rather than hemorrhage. Hence,
from previous reports [7, 8, 11, 13, 16-29] with a higher fre-
mass effect from the aneurysm with various clinical neuro-
quency beyond the age of 10 but no clear peaks.
logical signs and symptoms is more common in children [4]
Re-bleeding before securing of the aneurysm seems to but varies considerably between patient cohorts: 18,2% pre-
occur as often as in about half of the children [7, 11, 17, 40] sented with symptoms referable to mass effect in the mate-
and is thereby consistently more frequent than in adults rial of Sharma et al. [33], whereas the corresponding rate
where the incidence of re-bleeding varies between 16 and was as high as 46% in the patients of Kakarla et al. [16]. By
29% [11, 41, 42]. reviewing 431 reported cases [7, 8, 11, 13, 16-29], we found
that 17% of the children presented with neurological deficits
Some authors found that children with aneurysmal intrac-
and/or epilepsy, whereas in another 8% the aneurysm was
ranial hemorrhage more often present in a good clinical
found in the diagnostic work-up for chronic headaches. In
grade (Hunt and Hess grades 1-3, [43]) than adults [7, 8, 19,
7% the aneurysm was an incidental finding. The rate of inci-
20, 33, 26, 27, 44]. (Table 1) shows that 68% of the children
dental diagnosis was as high as 35% in Kakarla et al. [16].
were in Hunt and Hess grades 1-3, a number not too different
There was no clear age peak for when the aneurysm became
from the adult population. Fig. (3) summarizes the clinical
symptomatic (Fig. 4). The incidence of seizures in pediatric
grades from several reports providing adequate data [7, 8,

Fig. (2). Age at aneurysm rupture (data collected from previous reports providing adequate information [7, 8, 11, 13, 16-29]).

Fig. (3). Clinical grade according to Hunt and Hess [43] in males (light grey) and females (dark grey) with ruptured intracranial aneurysms
(data collected from previous reports providing adequate information [7, 8, 11, 13, 17-22, 24, 25, 27, 29]).
346 Current Pediatric Reviews, 2013, Vol. 9, No. 4 Sorteberg and Dahlberg

Fig. (4). Age when the aneurysm became symptomatic (non-hemorrhagic, data collected from previous reports providing adequate informa-
tion [7, 11, 13, 16, 18-21, 23-26]).
patients has been reported to be more than twice of that in 33%, therein a specific predominance of the ICA termination
adults (36% versus 17%, respectively [17]. Likewise, acute [4, 11, 27-29, 33, 34, 36, 45]. Krings et al. [4] found five
hydrocephalus was seen more often in children (36%) than times as many aneurysms on the ICA termination in children
in adults (25%) [17]. than in adults [4]. Reviewing 671 pediatric cases reported in
the literature [7, 8, 11, 13, 16-29, 33, 36, 37, 39, 40, 44, 46],
16% of all pediatric aneurysms occur at the ICA termination
ANEURYSM SITE
alone (Fig. 5), which compares to around only 5% in adults
There is consensus in that the anatomic sites of intracra- [38, 47]; i.e. the frequency of ICA termination (also denoted
nial aneurysms in children differ from those in adults, al- ICA bifurcation or ICA top) aneurysms is three times higher
though there are considerable variations between patient in children than in adults.
cohorts. Accounting for all internal carotid artery (ICA) loca- In adults, the anterior communicating artery (ACoA) is
tions (including the branching of the posterior communicat-
the most common aneurysm site, accounting for 25-39% of
ing artery), the ICA is the most common site in children with
all aneurysm locations [38, 47-49]. (Fig. 5) shows that the

Fig. (5). Localization of 671 pediatric (black columns) and 1021 adult (grey columns) intracranial aneurysms reported [7, 8, 11, 13, 16-29,
33, 36, 37, 39, 40, 44, 46]. Shaded columns indicate posterior circulation localizations. A1: anterior cerebral artery proximal to the anterior
communicating artery (AcoA), BA: basilar artery (locations other than terminus), ICA: internal carotid artery (localizations other than termi-
nus), M2 and M3: first and second branching of the middle cerebral artery (MCA), MCA bif: MCA bifurcation, P2/3: first and second
branching of the posterior cerebral artery (PCA), PICA: posterior inferior cerebellar artery, SCA: superior cerebellar artery, VA: vertebral
artery
Pediatric Aneurysms Current Pediatric Reviews, 2013, Vol. 9, No. 4 347
ACoA in children is only the third most common aneurysm arises from the arterial adventitia, they emerge often as fusi-
site with 12%. The second most common pediatric aneurysm form or «false» aneurysms [4]. Infectious aneurysms are
site is the middle cerebral artery (MCA) bifurcation with often situated at distal arterial branches and may be multiple.
16% (Fig. 5), which is quite similar to the frequency in 70% of the infectious aneurysms present with hemorrhage.
adults. In infants <1 year of age, however, the MCA carried
nearly 3 times as often an aneurysm as any other intracranial
TREATMENT
vessel [9]. Proust et al. [11] found MCA aneurysms to be the
second most common site in children aged 7 to 16 years with The treatment of pediatric patients with intracranial sac-
36% of their cases harboring MCA aneurysms; 50% of them cular aneurysms seems to follow the institutional protocols
were localized on the first MCA branch (M2 level). developed for adult aneurysm patients [11, 33, 54]. Accord-
Posterior circulation aneurysms are overrepresented in ingly, treatment often is dependent on the traditions of the
the pediatric population with a rate of 21%, which corre- neurosurgical center and ranges from surgically clipping all
sponds to almost three times the incidence found in adults [4, patients [7, 17, 36] to endovascular treatment in all [23] or
the majority of the patients [13].
38, 47] (Table 1). (Fig. 5) illustrates a frequency of 5% for
vertebral artery aneurysms in children, whereas the corre- The long life expectancy of children challenges in par-
sponding number in adults is less than 2% [38, 47]. Like- ticular the durability of treatment. In this respect, surgical
wise, aneurysms were found in 11,4% on the basilar artery in treatment may be superior to endovascular approaches [16].
children (7,6% basilar artery + 3,8% basilar termination), but Sanai et al. [8] found that children treated endovascularly
only in 4-8% in adults, respectively [38, 47]. were four times as often in need to further treatment as com-
pared to those that were surgically treated. Stiefel et al. [22]
Multiple aneurysms are found in approximately 14% of
preferred to clip pediatric aneurysms (except those on the
adult patients, with a range from 7-30% [38, 47]. This equals
the findings of Lasjaunias et al. [13] with 15%, Sharma et al. basilar artery) because they were not convinced of the dura-
[33] with 16%, and Kakarla et al. [16] with 31%. Others, bility of endovascular treatment. Likewise Sanai et al. [8]
however, reported a lower incidence of multiple aneurysms built a strong case for surgical treatment as they observed a
higher recurrence rate in endovascularly treated aneurysms
in children as compared to adults [7, 20, 50].
along with a higher rate of de novo aneurysm formation in
children. They attributed the latter to catheter manipulation
ANEURYSM FEATURES causing small arterial wall defects as the potential source of
aneurysm formation [8].
Giant aneurysms ((cid:2) 25 mm) are found much more fre-
quent in children than in adults. The numbers, however, vary The higher fraction of complex aneurysms in children re-
widely from an incidence of zero to 68% [7, 8, 11, 16, 20, quires more often advanced treatment beyond standard aneu-
23, 28, 33, 40, 44]. Krishna et al. [17] reported the incidence rysm clipping or coiling, including intracranial and extracra-
of giant aneurysms in children to be 13,6%, whereas the cor- nial-intracranial bypass procedures, hypothermic arrest and
responding number in adults was 6,5%. Proust et al. [11], on aneurysm resection [8, 11, 16, 19, 44]. Pediatric patients
the other hand, found a frequency of giant aneurysms around represented 10.2% of all cardiac standstill procedures in the
14% in both pediatric and adult patients. In infants <1 year, material of Karkarla et al. [16] due to the large size and pos-
the mean size of aneurysms was 18mm, with 30/131 being terior fossa localization of many of the aneurysms. By re-
giant [9]. (Table 1) shows that the frequency of giant aneu- viewing 431 published pediatric cases, there emerges a clear
rysms in children and adolescents is reported to be 19%. preference for surgical treatment accounting for 55% of all
Pediatric giant aneurysms seem to favor the vertebrobasilar cases versus 12% that were treated endovascularly [7, 8, 11,
arteries with reported incidences in that specific location 13, 16-29]. Sixteen percent were treated with therapeutic
ranging from 8-100% [10, 11, 19, 20, 23, 26, 36, 37, 44, 45, parent artery occlusion, 13% were managed conservatively,
51, 52]. whereas 4% had antibacterial treatment only [7, 8, 11, 13,
16-29]. On the other hand, it is reasonable to assume that the
Dissecting and fusiform aneurysms are relatively com-
long-term effect of endovascular treatment of pediatric pa-
mon in children in contrast to adults who typically carry sac-
tients is not yet established due to the small number of pa-
cular aneurysms. In the material of Lasjaunias et al. [13] the
tients treated, the relatively short time of follow-up, and the
fraction of dissecting aneurysms in children was as high as
enormous evolution of endovascular techniques [55].
45%. Krings et al. [4] stated that the incidence of dissecting
aneurysms is four times higher in children than in adults. Therapeutic artery occlusion is a quite common treatment
Fusiform or dolichoectatic aneurysms accounted for 51% of option in pediatric aneurysm patients, with numbers as high
the aneurysms in the pediatric patients of Sanais et al. [8]. as 64,7% for parent artery sacrifice [13, 23] and 11,8%
Non-traumatic dissecting aneurysms are most commonly proximal artery occlusion with flow reversal in the artery
found at the level of the supraclinoid ICA, the MCA, and in carrying the aneurysm [13]. This treatment option was cho-
the posterior circulation, preferably the P1and P2 segments sen in 16% of reported cases [7, 8, 11, 13, 16-29]. The toler-
of the posterior cerebral artery [53]. MCA aneurysms in ance to therapeutic vessel occlusion is reported to be better
children tend to be large and/or ectatic, often including M2 in children than in adults [18, 26, 28].
branches in the pathological vessel section [18].
Lasjaunias et al. [13] and Liang et al. [20] reported on a
The rate of infectious aneurysms (often referred to as high fraction of pediatric patients in which the aneurysm had
“mycotic” aneurysms) is higher in children than adults (8% thrombosed spontaneously, which is a rather uncommon
versus 5%) [9, 17, 38]. As this type of aneurysm usually event in the adult population. In dissecting aneurysms, mural
348 Current Pediatric Reviews, 2013, Vol. 9, No. 4 Sorteberg and Dahlberg
hematoma seems to be the most important promoting factor needs to consider that a large portion of the children had
for spontaneous thrombosis and healing of the aneurysm non-ruptured aneurysms where outcome can be anticipated
[21]. to be different from that in subjects that have suffered hem-
orrhage.
A very important peculiarity that needs to be mentioned
is the tendency to delayed treatment in children [11, 17]. Approximately 90% of the children that had their aneu-
Krishna et al. [17] observed an interval of more than 14 days rysm treated were in Glasgow outcome scale (GOS, [58]) 5
from ictus to surgery in 41% of their pediatric patients, com- or 4 (i.e. excellent or good result) in the reports by Sharma et
pared to 27% of the adult patients. Delayed diagnosis of an- al. [33] and Liang et al. [20]. Outcome in infants younger
eurysmal SAH increases the chance of re-hemorrhage from than one year was similar or slightly better than in adults
the unsecured aneurysm, with all its possible deleterious with 50% in GOS 5 [9]. In parallel to the treatment results in
effects, thereby seriously affecting outcome. adults, the outcome in children has improved over the last
decades [35] due to a shift to early securing of the aneurysm,
the development of microsurgical techniques and endovascu-
OUTCOME
lar treatment options, along with improvements of post-
Many authors report a more favorable outcome in the pe- operative care.
diatric patient cohort than in adults. There is, however, con- Overall, a good outcome, defined as GOS 5 or 4 is re-
siderable variation between reports. Lv et al. [23] obtained a ported in 68% of children with intracranial aneurysms (Table
good outcome in 96% of the pediatric patients by predomi- 1), this number, however, includes reports merely consider-
nantly securing the aneurysms with parent artery occlusion
ing outcome of survivors. The true fraction of those with
(including 3 cases of MCA occlusion), however 14 of their
good outcome is hence lower.
25 patients had not hemorrhaged and the clinical state of
In case of ruptured aneurysms, (Table 2) the clinical
those with ruptured aneurysms is not given. It is worth not-
grade immediately following the SAH is a strong predictor
ing that results in the adult subgroup selected for treatment
of outcome ((Fig. 6), p<0.0001 Kruskal-Wallis test).
with parent artery occlusion are equally good with zero one
year mortality [56, 57]. In the material of Krishna et al. [17], None of the children in Hunt and Hess grade 5 (i.e. those
82% of the children had a favorable outcome versus 59% of who are immediately comatose from their hemorrhage) sur-
the adults. Comparing outcome in children and adults one vived to a good clinical outcome and mortality in that sub-
Table 2. Outcome Accumulated from Reports [16, 18, 20-23, 33, 35] Providing Adequate Data. GOS: Glasgow Outcome Scale [58]

Good result - independent Poor result - dependent dead
GOS 5 GOS 4 GOS 3 GOS 2 GOS 1
Unruptured aneurysms 66% 21% 7% 1% 5%
Hunt and Hess grade 1 85% 11% 2% 0 2%
Hunt and Hess grade 2 68% 22% 2% 2% 6%
Hunt and Hess grade 3 44% 30% 10% 2% 14%
Hunt and Hess grade 4 12% 30% 28% 9% 21%
Hunt and Hess grade 5 0 0 13% 5% 82%

Fig. (6). Most children that were in good clinical grade (Hunt and Hess [43] grades 1-3) had an excellent (GOS5) or good (GOS4) outcome,
whereas many of the children presenting in a poor clinical grade (Hunt and Hess grades 4 and 5) died (GOS1) or survived to a dependent life.
GOS: Glasgow outcome scale [58]. HH: Hunt and Hess grade.
Pediatric Aneurysms Current Pediatric Reviews, 2013, Vol. 9, No. 4 349
group was 82% [7, 8, 11, 13, 16-29]. Mortality numbers in in the posterior fossa. Second, regarding the long life-
children versus adults seem to be similar [7, 11, 16, 17, 22]. expectancy of pediatric patients, the durability of treatment
In infants <1 year mortality was 28% [9]. Approximately is more crucial than in the typical adult aneurysm patient that
12% of adults with aneurysmal SAH succumb to their bleed is in its 5th decade of life when becoming symptomatic. En-
before they can reach medical attention [32, 59]. The corre- dovascular treatment with coils or coiling through a stent
sponding number in children is unknown. may not accomplish life-long occlusion of the aneurysm.
Furthermore, endovascular procedures are difficult to per-
Cerebral vasospasm represents a major risk factor for
form in the youngest children and many centers may not
poor outcome or death following SAH. Angiographic vaso-
have sufficient experience to treat the child themselves. Who
spasm was observed equally in children and adults, however,
should treat children with intracranial aneurysms? This ques-
clinical vasospasm is more infrequent in children [11, 17,
tion is difficult to answer in general terms and would have to
60]. Krishna et al. [17] found clinical vasospasm in 9,5% of
be decided individually, based and the specific nature of the
their pediatric patients versus 28,5% in adults, respectively.
aneurysm and the availability of treatment options at the
Proust et al. [11] described six children with angiographic
hospital the child is admitted to. Many institutions do not
severe vasospasm that all were asymptomatic. Lasjaunias et
have a 24 hour availability of both cerebrovascular surgeons
al. [13] observed that the tolerance to cerebral vasospasm
and endovascular therapists. In that regard, one also has to
was good in children, even after treatment with therapeutic
keep in mind that many pediatric aneurysms are complex
parent artery occlussion which poses an extra challenge with
and pose special requirements to the skills of the therapist.
regard to developing cerebral ischemia. In the material of
For sure, the pediatric aneurysm patient requires a broader
Sharma et al. [33], 10/43 children were diagnosed with vaso-
multidisciplinary cooperation involving vascular neurosur-
spasm and 20% of them developed manifest cerebral infarc-
geons, neurointerventionalists, pediatricians, pediatric ICU
tion. Their findings concur well with that of Stiefel et al.
staff, psychologist and a rehabilitation team with experience
[22]; who observed a 17% frequency of stroke due to vaso-
in treating pediatric stroke.
spasm, wherein all occurred in children younger than 2
years. There is another challenge to pediatric aneurysm pa-
tients too: this condition is so rare that aneurysmal SAH
The long-term prognosis of children with intracranial an-
would not necessarily be included in the diagnostic arma-
eurysms is influenced by a higher risk to develop de novo
mentarium when a child presents with headache. This can
aneurysms than adults [14]. Hetts et al. [14] found that 8,4%
lead to both patient and doctor related delay in diagnosis
of their pediatric patients developed new or enlarging aneu-
and treatment. Accordingly, there is a higher rate of re-
rysms within an average of less than five years of the initial
bleeding of ruptured aneurysms in children than in adults
diagnosis. This compares to a corresponding 1,5% rate re-
[7, 11, 17, 40] which may effect the outcome dramatically
ported in adults [61]. Kakarla et al. [16] found an annual
to the worse. The reported numbers do not include the chil-
recurrence rate of 2,6% with an annual rate of de novo for-
dren that never made it to a hospital after their bleed or re-
mation or aneurysm growth of 7,8% in children.
bleed. In the adult population an immediate death toll of
approximately 12% of all aneurysmal SAH is anticipated
DISCUSSION [32], one could assume this rate to be similar or higher in
the pediatric population. To prevent re-bleeding, children
Pediatric intracranial aneurysms are very rare, with ap-
should be diagnosed as early as possible, i.e. pediatricians
proximately 1200 cases reported between 1939 and 2011
should keep the possibility of aneurysmal hemorrhage in
worldwide. No real large series or multicenter studies so far
mind when a child presents with sudden headache. In the
exist and reports on pediatric intracranial aneurysms reflect
presence of nuchal rigidity, a lumbar puncture, CT scan, or
institutional experiences acquired over a large time-span or
MRI would be performed, usually leading to the correct
are published as case reports. Consequently, the results from
diagnosis. With that clinical presentation, if meningitis is
the various studies are inconsistent and partly divergent. One
suspected and a lumbar puncture is performed one should
could also presume that it is not only the limited number of
also include analysis for xanthochromia. There would be a
patients, but also differences in institutional and regional
larger problem if the child is in a relatively good clinical
referral practices that contribute to the diversity of findings.
condition apart from the headache, as routinely screening
Furthermore, treatment strategies and the available treatment
with CT or MRI would not necessarily be justified. Less
armamentarium has changed dramatically over the last dec-
than 3% of cases with adult sudden headache are due to
ades and reports from the 60ies should not be compared with
aneurysm bleeds [62], and the chance of finding intracra-
reports from the current century.
nial hemorrhage in a child, respectively, would be even
There is consensus, though, in that pediatric aneurysms less. Individuals younger than 18 years seeking medical
represent a pathophysiologic entity different from their adult attention for headache account for 0,8% of all emergency
counterparts - they are not simply "standard" saccular aneu- department visits in the United States [63], with a patho-
rysms occurring in very young humans. This also means that logical finding in less than 2% of them [63]. On the other
management strategies acquired for adults cannot be fully hand, as long as the diagnosis of a ruptured aneurysm is not
transferred onto the pediatric patient population. First, pedi- established, the danger of re-bleed is eminent. Re-bleeding
atric aneurysms most often are complex and hence require in adults is identified as a strong predictor of poor outcome
more challenging treatment strategies like intracranial bypass and death.
procedures or therapeutic parent artery occlusion. Approxi-
The mortality in children and adults is reported to be
mately one third of the aneurysms are giant, exerting signifi-
similar. Likewise, studies that included children with a clini-
cant tumor effect to delicate brain structures, predominantly
cal presentation comparable to the adult aneurysm cohort
350 Current Pediatric Reviews, 2013, Vol. 9, No. 4 Sorteberg and Dahlberg
found similar outcomes [11, 22]. One could hence suspect ACKNOWLEDGEMENTS
the notion of favorable outcome in children with intracranial
Declared none.
aneurysms to be a myth. Another predictor of poor outcome
is the occurrence of severe vasospasm. There are several
reports on the good tolerance of cerebral vasospasm in chil- ABBREVIATIONS
dren, which should give them an advantage in terms of out-
come compared to adults. Moreover, patients with ruptured ACoA = anterior communicating artery
intracranial aneurysms have a higher mortality and poorer A1 = anterior cerebral artery proximal to the
outcome than those without intracranial hemorrhage unless AcoA
the aneurysm is giant. Giant aneurysms in adults, even if
BA = basilar artery
unruptured, have a poor prognosis and a mortality rate of up
to 66%, with those in the posterior circulation having the CT = computed tomography
poorest odds of all [56, 64]. A possible explanation for chil-
GOS = Glasgow outcome score
dren not having a lower mortality and morbidity could be the
high percentage of giant aneurysms in the posterior circula- HIV = human immunedeficiency virus
tion in children. Another pitfall in establishing outcome in
ICA = internal carotid artery
children with cerebral aneurysms are differences in outcome
measures between various reports. In many studies, outcome MCA = middle cerebral artery
has been considered as "good" or "excellent" without using
M2 and M3 = first and second branching of the MCA
any standardized mode of measurement or rigorous criteria
for assessment. None of the reports included neuropsy- MRI = magnetic resonance imaging
chological investigations. In adults, even patients scored as SAH = subarachnoid hemorrhage
excellent or good outcome (GOS 5 or 4) by a neurosurgeon
may display significant impairments on neuropsychological PCA = posterior cerebral artery
tests and in Quality of life questionnaires [65]. In children Pericall = pericallosal artery
one could assume similar effects on brain function or even
P2 and P3 = first and second branching of the PCA
worse impact in very young children whose brain is still de-
veloping and thereby could be more susceptible to the con- PICA = posterior inferior cerebellar artery
sequences of hematoma, treatment trauma and secondary
SCA = superior cerebellar artery
ischemic damage. Outcome will also have to be dichoto-
mized into early outcome, i.e. up to one year past diagnosis VA = vertebral artery
versus the long-term outcome. In many reports data for the
long-term results in pediatric aneurysms were, however, lim-
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Received: December 21, 2012 Revised: July 19, 2013 Accepted: September 12, 2013